BELLEVUE — When Lakeside senior AJ Adekoya headed for the bench late in the fourth quarter, he received the loudest applause of the game.

When Lakeside’s coaches huddled in the locker room to give out the game ball, it was a unanimous decision. For the first time this season, it had to be Adekoya.

Adekoya’s statistics from No. 4 Lakeside’s 68-61 victory against No. 2 Mercer Island in the Sea-King 3A District semifinal Thursday won’t jump off the page: four points, three rebounds, two steals, two assists and one block.

But in the second half, in just nine minutes of work, the lightly used Adekoya made some of Lakeside’s biggest plays.

“In the second half we knew we needed energy, and we knew we really needed guys to bring the tempo up,” Lakeside (20-4) coach Tavio Hobson said. “He’s a senior, a guy that’s really dedicated to the team, and he came in and gave us really big minutes.”

When Mercer Island (21-3) cut Lakeside’s lead to six early in the fourth quarter, Adekoya answered with a rebound and layup. He provided that spark throughout the fourth.

Tramaine Isabell, Lakeside’s junior guard, again delivered a big performance. He scored 25 points — the ninth time in his past 11 games in which he has scored at least 18 points — and had 13 in the decisive second quarter, dominated by Lakeside 25-9.

“We think when he’s locked in and focused, he can really go,” Hobson said. “Today was really an example of that.”

Kaleb Warner led Mercer Island with 24 points, including 14 in the second half.

D’Marques Tyson scored 19 points for the Lions, who will play Rainier Beach on Saturday at Bellevue Community College in the Sea-King 3A District championship game.

Other boys semifinal

Rainier Beach 59, Franklin 45

Captain Marquis Davis returned from a one-game suspension to lead the Vikings (21-3, 14-1 Metro) with 14 points. The only player to finish in double figures for the Quakers (16-8, 11-4) was Eugene Artison, who had 10.

Girls semifinals

Seattle Prep 43, Bellevue 41

The Panthers (20-4, 14-2 Metro) came back after trailing 14-9 at the end of the first quarter, handing Bellevue (22-2, 13-1 Kingco) its second defeat of the season. Quinn Glosniak led the way for Prep, scoring a game-high 14 points.

Cleveland 68, Mercer Island 42

The Eagles (22-2, 15-0 Metro) led 23-10 after the first quarter as Mikayla Roper had 13 first-quarter points and finished with 23. She was 10 of 14 from the field. Kris Brakkman scored 17 points for Mercer Island (20-6, 11-3).

Pete Treperinas of The Seattle Times staff contributed to this report.

Jayson Jenks: 206-464-8277 or jjenks@seattletimes.com; on Twitter: @jaysonjenks. Jayson Jenks covers the Seahawks for the Seattle Times. He also provides coverage of other Seattle-area teams throughout the year.